Road conditions may change dynamically due to a wide variety of causes where no prior avoidance notification is available to drivers. A common result of a driver's sudden realization of a hazardous condition is to brake hard or to swerve to avoid the hazard. This may be true for both transient traffic conditions, such as those caused by a traffic accident, and for chronic road conditions, such as at a blind turn where drivers regularly slow down. Alerting drivers of impending road conditions may be advantageous.